Cenozoic Era, the most recent great division of geological time, including the present. It follows the Mesozoic (middle-life) Era. The Cenozoic Era is divided by most geologists into the Tertiary and Quaternary periods. Geologists estimate that the Cenozoic Era began some 65,000,000 years ago.Cenozoic Era animals date from 65 million years ago to the present.
Crack open any science textbook and the authors will tell you that such things don't happen. So how did a couple of paleontologists and an acid bath turn that widespread belief on its head?
Every time a new fossil is found, one of the first things scientists determine is how old that fossil really is. But how do they determine it, and how can they be completely accurate?